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00045 #include "dsp.h"
00046
00047 #define A 0.63661977236758134307553505349036 // 1/CST
00048 #define B 0.10610329539459689051258917558125 // (1/2)/3/CST
00049 #define C 0.047746482927568600730665129011754 // (1*3)/(2*4)/5/CST
00050 #define D 0.028420525552124167101586386315975 // (1*3*5)/(2*4*6)/7/CST
00051 #define E 0.019341746556306724833024068465127 // (1*3*5*7)/(2*4*6*8)/9/CST
00052 #define F 0.01424255882782586101340863223362 // (1*3*5*7*9)/(2*4*6*8*10)/11/CST
00053
00054 #if defined(FORCE_ALL_GENERICS) || \
00055 defined(FORCE_GENERIC_OP16_ASIN) || \
00056 !defined(TARGET_SPECIFIC_OP16_ASIN)
00057
00058
00059
00060
00061 dsp16_t dsp16_op_asin(dsp16_t num)
00062 {
00063 S32 num_sqr, res;
00064 dsp16_t num_abs;
00065
00066 num_abs = dsp16_op_abs(num);
00067
00068 #if DSP16_QB < 15
00069
00070 if (((S32) num) >= ((S32) DSP16_Q(1.)))
00071 return DSP16_Q(0.5);
00072 if (((S32) num) <= ((S32) DSP16_Q(-1.)))
00073 return DSP16_Q(-0.5);
00074 #endif
00075
00076
00077 if (num_abs > DSP16_Q(0.5))
00078 {
00079 num_abs = dsp16_op_sqrt((DSP16_Q(1.)-num_abs) >> 1);
00080 num_abs = DSP16_Q(0.5) - (dsp16_op_asin(num_abs) << 1);
00081 return (num < 0)?-num_abs:num_abs;
00082 }
00083 else
00084 {
00085 num_sqr = (((S32) num)*((S32) num)) >> DSP16_QB;
00086 res = (num_sqr*DSP16_Q(D)) >> DSP16_QB;
00087 res = (num_sqr*(res + DSP16_Q(C))) >> DSP16_QB;
00088 res = (num_sqr*(res + DSP16_Q(B))) >> DSP16_QB;
00089 num = (((S32) num)*(res + DSP16_Q(A))) >> (DSP16_QB + 1);
00090
00091 return num;
00092 }
00093 }
00094
00095 #endif
00096
00097 #if defined(FORCE_ALL_GENERICS) || \
00098 defined(FORCE_GENERIC_OP32_ASIN) || \
00099 !defined(TARGET_SPECIFIC_OP32_ASIN)
00100
00101
00102
00103
00104 dsp32_t dsp32_op_asin(dsp32_t num)
00105 {
00106 S64 num_sqr, res;
00107 dsp32_t num_abs;
00108
00109 num_abs = dsp32_op_abs(num);
00110
00111 #if DSP32_QB < 31
00112
00113 if (((S64) num) >= ((S64) DSP32_Q(1.)))
00114 return DSP32_Q(0.5);
00115 if (((S64) num) <= ((S64) DSP32_Q(-1.)))
00116 return DSP32_Q(-0.5);
00117 #endif
00118
00119
00120 if (num_abs > DSP32_Q(0.5))
00121 {
00122 num_abs = dsp32_op_sqrt((DSP32_Q(1.)-num_abs) >> 1);
00123 num_abs = DSP32_Q(0.5) - (dsp32_op_asin(num_abs) << 1);
00124 return (num < 0)?-num_abs:num_abs;
00125 }
00126 else
00127 {
00128 num_sqr = (((S64) num)*((S64) num)) >> DSP32_QB;
00129 res = (num_sqr*((S64) DSP32_Q(F))) >> DSP32_QB;
00130 res = (num_sqr*(res + ((S64) DSP32_Q(E)))) >> DSP32_QB;
00131 res = (num_sqr*(res + ((S64) DSP32_Q(D)))) >> DSP32_QB;
00132 res = (num_sqr*(res + ((S64) DSP32_Q(C)))) >> DSP32_QB;
00133 res = (num_sqr*(res + ((S64) DSP32_Q(B)))) >> DSP32_QB;
00134 num = (((S64) num)*(res + ((S64) DSP32_Q(A)))) >> (DSP32_QB + 1);
00135
00136 return num;
00137 }
00138 }
00139
00140 #endif